Unmanned vehicles, including Unmanned Aerial Vehicles (UAV or drones), Unmanned Surface Vehicles, and Unmanned Underwater Vehicles, have proven useful for a wide variety of commercial, scientific, and military applications. However, such vehicles are typically used for relatively short-duration missions, partly due to the constraints of carrying sufficient fuel for extended missions, and partly due to the need for remote piloting of the vehicle. Therefore, in order to enhance utility for very long duration applications, such vehicles should be substantially autonomous, and able to operate without requiring frequent refueling.
Some unmanned vehicles have been used as long-term platforms when moored in place, or even permitted to drift on the water's surface or in the atmosphere, the lack of directed mobility may critically limit the capabilities of such platforms.
What is needed is an autonomous vehicle capable of powered flight that is additionally able to refuel autonomously and in the absence of a fueling infrastructure.